Hydraulic artificial hand



Dec. 5, 1939. J SARGESON 2,182,214

HYDRAULI C ARTIFI C IAL HAND Filed Aprillo 1937 2 sheets-sheet 1 ATTI Dec. 5, 1939. 1 SARGESON 2,182,214

HYDRAULIC ARTIFICIAL 'HAND Filed April 10, 1957 2 sheets-sheet 2 Patented Dec. 5, 1939 UNITED STATES PATENT OFFICE 9 Claims.

The invention relates to a hydraulic gripping device for a person who has lost a hand or arm. The device is adapted to be carried by the stump of the limb according to the nature of the ampu- I tation. The invention essentially concerns-a device for gripping objects both for the purpose of holding them. and for manipulating them. The appliance may be applied to a stump of an arm by means of a socket or corset or it may be in- 19 corporated in an artificial arm.

The invention comprehends a pair of relatively movable jaws for positively gripping an object irrespective of the spread of the jaws, and a hydraulic actuating mechanism. One of the jaws is connected to a piston of a ilud cylinder into which fluid is forced by a pump strapped to a leg of the wearer. The pump is equipped with a reciprocal piston depressible by a pedal having an associated locking mechanism and a trip mechanism for release purposes. Accordingly, by carrying the ypump on one foot, the other foot is available for operating the control mechanism.

y Having described the nature and main object of the invention, subsidiary objects and advantages will be apparent as the invention is recounted in greater detail.

Referring to the drawings, Figure l illustrates the manner in which the invention is worn.

Figure 2 is a side elevation of the uid cylinder and gripping jaws carried by the amputated limb.

Figure 3 is a side view of the pump attached to a shoe.

Figure 4 is a top plan view of the pump.

Figure 5 is a vertical section of the pump.

Figure 6 is a further side view of the pump, butI showing the pedal released by the trip mechanism.

Figure '7 is alongitudinal section of the fluid cylinder and the jaws.

Figure 8 is a cross section thereof taken on line 8-8.

Like numerals of reference indicate correspending parts in each figure throughout the a' drawings.

In carrying out the invention, it is proposed that the uid cylinder 9 shall be rigidly mounted in a conventional socket or corset member III fitted on the stump of the amputated limb according to the nature of the amputation. The cylinder has a nipple II connected to a length of flexible tubuing I2 extending to the pump I3; which pump will be later described in detail.

The cylinder is supplied with a reciprocal piston I4 having an outwardly protruding rod IiiV extending to the movable jaw I6 opposite thexed jaw II which is preferably shaped as shown. The rod I5 is axially compressible to a certain degree by means of the interposition of a resilient element, such as the spring I8. This is achieved 5 by making the rod of an outer telescopic part I9 rigid with the jaw I6, and an inner telescopic part I9 rigid with the piston i4. The spring ls interposed between'the piston and the inner end of the .telescopic part I9. l0

By this construction, it will be gathered that as the piston is outwardly urged by iiuid pressure, the spring will yield when the jaws close on an object and thus the compressive force will prevent it from. loosening in the jaws. 4

The rigid jaw I1 is integral with orse'cured to e. stock co-extensive with the cylinder, which stock is constructed to form a longitudinal guiding connection for the movable jaw I6. For example, the guiding connection may consist of a guide piece 2| slidably mounted in a channel 22 and rigid with the movable jaw. The channel may be formed in the forepart of the stock and the rear part of the stock may be hollow to accommodate a resilient member, such as the end- 2; less elastic band 23 that is connected to the guide piece 2l so as to retract the jaw I6 together with its operating piston. This retractile movement forces the fluid back into the pump when the pump piston is released by the trip mechanism.

To adjust the angular position of the jaws, it is desirable that they be so mounted as to be rotatable about the cylinder axis. This may be accomplished in convenient manner, such as, for example, by the provision of a pair of spaced rings 24, 24 rotatably encircling the cylinder 9 and endwise shouldered by an intervening collar 25 rigid with the cylinder. These rings are integral with or secured to the stock 20 so as to allow the jaws to swivel as a unit about the cylinder.

To retain the jaws in any angular position relative to the cylinder,y a locking mechanism is employed, which is shown as consisting of a detent pin 26 slidably mounted in the stock 20 for selective engagement in any one of a circumferential series of radial holes 2'I in the collar 25. The detent pin is operable by a lever 28 pivoted at 29 and furnished with a spring 30 for normally pressing the detent pin in the direction of the holes 2l. The pin is releasable from the collar by depression of the free end of the lever.

To strengthen the rotatable mounting of the stock on the cylinder, a rear ring 3| may be resorted to, which is similar to the rings 24. The

. sideof the leg and the pivot 34 is aligned with centJ side of the cylinder.

the ankle joint so as to facilitate movement of the foot. The upper end of the cylinder may `have a strap 35 for attachment about the leg. The iiexible tubing I2 communicates with the lower end of the cylinder.

The reciprocal piston 36 of the pump has an upwardly directed rod 31 fastened to a guide 38 freely slidable within the bore and. projectingA outwardly through azslot 39 in the upper end of the cylinder clear of the travel or stroke of the piston. The projecting part 40 of the guide is pivoted at 4I to a depending detent 42 coextensive with the cylinder, but on the far side of the plate 34.

The pivotal connection of the detent is so lar- ,ranged that the lower end of the detent may have a limited'movement to and away from the adja- This lower end'carries a fixed tooth 43 engageable with teeth of a ratchet bar 44 united with the cylinder.

A pedal 45 is pivoted at 46 to the lower end of the detent so that it may swing from a vertical to a horizontal position. It is sustained by a shoulder in known manner in its unfolded horizontal position so as to enable the wearer of the appliance to raise his other foot and place it on the pedal for the purpose of depressing it to eject fluid into the other cylinder 9. The pedal is vertically folded when not in use.

It will be evident that by this construction the detent automatically locks the piston 36 in any position to which it is lowered, and that the jaw i6 will thus be held in its advanced position until the detent is released from the toothed engagement with the ratchet.

The pedal release mechanism herein disclosed comprises a parallel bar 4'! swingable outwardly sisting of a bent out portion of this bar.

vso

by links 48 and normally held raised by a spring 49. The lower end of the bar has a trip 50 con- The pivotal pin 46 of the detent is outwardly projected from a side of the pedal 45'so as to-be disposed in the path of movement of the bar 4l.

It Will be manifest that by this construction the detent can be released from whatever position it happens to be in. The wearer merely places his other foot on the trip 50 to urge it down wardly. 'I'his throws the parallel bar 4 1 outwardly into contact with the pin 46 urging the lower end of the detent away from the ratchet to free the toothed engagement. When the detent is released, the resilient member 23 drivesthe fluid back into the pump cylinder, raising the piston thereof ready for recurrent operation. The return of the piston may be assisted by a spring 5l connected to the detent.

'What I claim is: j

1. A hydraulic artificial hand comprising'a cylinder, a piston therein adapted to be advanced by liquid pressure, a rigid jaw, a movable jaw guided for opening and closing 'movement relative to the rigid jaw, supporting means for the jaws, va compressible mechanical connection between the said piston and said movable jaw for eifectinga closing movement of the movable jaw by advance movement of the piston, a pump connected to the cylinder for passage of liquid therebetween, a piston therein for delivery of liquid to the cylinder, releasable means for precluding y the discharge of liquid delivered to the cylinder so as to ,lock the movable jaw against retrograde movement, and resilient means for retracting the movable jaw and the cylinder piston when the liquid .is allowed to discharge from the cylinder.

2. A hydraulic artificial hand comprising the combination with a fluid cylinder having a. piston rod extending axially therefrom, of a stock co-A extensive with the piston rod to one side of the cylinder, a pair of jaws transversely extending from the stock, one of said jaws being rigid with the stock and the other being connected to the Ypiston rod and slidably associated with the stock, and means whereby the stock is rotatably mountedon the cylinder to adjust the transverse angular position of the jaws relative to the cylinder.

3. A hydraulic artificial hand Vcomprising a.

pump adapted to be vertically attached to the leg of a person, said pump having a depressable piston, means for lockingthe piston in a depressed position, a pedal adapted to depress the piston,

1 a trip carried by the pump for releasing the locking means, a tubing extending from the pump, a fluid cylinder carried by 'an amputated arm of the person and connected to said tubing, a piston in said cylinder, and gripping elements associated with the piston of said cylinder for operation thereby.

4. A hydraulic artificial hand in accordance with claim 3, in which the pump has a plate pivoted in the vicinity of itslower endfadapted for vattachment to a shoe so that the pivot axis will be in alignment with thefankle joint of the foot, and in which the pump has a strap at its' upper end adapted for fastening it to the leg of the wearer.

5. A hydraulic artificial hand comprising a cylinder,v a piston reciprocally mountedtherein,. a pair' of clamping jaws carried by the cylinder, one of 'the jaws being stationary and the other movable, an axially compressible rod connecting the piston to the movable j'aw and consisting of a pair of interitti'ng members having a resilient element so interposed as to be compressible when the piston urges the movable jaw into clamping engagement, and a pump connected to the cylinder for exerting hydraulic pressure on the aforesaid piston therein to close .the `said jaws.

6. A hydraulic artificial hand comprising a cylinder, a piston reciprocally mounted therein, a pair of clamping jaws carried by the cylinder,

one of thejaws being stationary and the other movable, an axially compressible rod connectling the piston to the movable jaw, a pump connected to the cylinder for exerting hydraulic pressure on the piston therein to thus advance the vmovable -jaw aforesaid into clamping engagement, means for retaining the movable jaw in advanced position comprising a stationary4 ratchet bar,`a co-acting detent shiftable by operation of the pump into locking engagement with the ratchet bar, means `connected with the .detent to retain the 'cylinder-piston in an advanced position when the detent is engaged with the ratchet bar, and means. for disengaging the detent consisting of a plurality of links each of which is pivoted at one" end to a support, a spring-retracted bar pivoted to the other end of said links and disposed alongsidelof the detent, a depressible trip carried by the bar, and a member carried by the detent and projecting into the path of movement of the bar.

7.*A hydraulic articial hand comprising a pump adapted to be vertically attached to the leg of a person, said pump being composed of a cylinder having a displacement chamber in the lower portion thereof, a depressible piston in the cylinder for discharge of fluid from the chamber in the down stroke, an upwardly extending rod connected to the piston and guidably supported by the cylinder, an elongated detent disposed exteriorly of the cylinder and lengthwise thereof; the lower end of the detent being adapted to engage teeth of a ratchet bar and the up tated arm of the person and connected to said tubing, a piston in this cylinder, and gripping elements associated with the last mentioned piston for operation thereby.

8. A hydraulic artificial hand comprising a cylinder, a piston therein operated by iluid pressure, jaw mechanism actuated by the piston, a

pump connected to the cylinder for passage of fluid therebetween, a fluid piston in the pump, means for actuating this piston, means for locking the jaws in' a gripping position, and means for releasing the locking means. v

9. In combination, an artificial limb member including a movable element adapted to be attached to a human body, means for actuating said movable element comprising a rst cylinder adapted to be attached to said body, a piston in said first cylinder connected for operation by movement of said body, a second cylinder mounted in said artificial limb member, an operative connection between said first cylinder and said second cylinder comprising a conduit adapted to contain an inelastic fluid, a piston in said second cylinder, and a rod affixed to said last named piston and attached through resilient means to said movable element of said artificial limb member for-the actuation thereof.

JOHN SARGESON. 

